This invention relates to dust/air pick-up systems for squeeze-type dust dispensers. It provides a means to apply light coatings of powdered material with a high degree of accuracy at relatively great distances regardless of the dispensers attitude.
Powders have been in use for hundreds of years and there are patents for dust dispensers dating back to the 19th century, for example, Fitchtenberg""s, Insect Destroyers (Patent No. 156, 696), patented in 1874. Safer powdered pesticide products for use in homes, gardens, institutions and industries enjoy increasing popularity. Powdered products of other types including foot powders, herbicides, powders used in manufacturing, in mold releases, etc. currently utilize a wide array of dispensers to apply them.
U.S. Pat. No. 2,450,205 shows a compressible powder dispenser. Positioned within the casing and supported by the top member is the powder exit tube, the upper end of the tube being open outwardly at the casing and the lower end of the tube being positioned above the bottom member. Positioned longitudinal to the exit tube and clamped in place is an air-circulating tube and positioned over each end of the air-circulating tube is a disc of air-pervious, powder impervious material to prevent the passage of powder into the air-circulating tube.
U.S. Pat. No. 2,896,825 discloses another type of dispensing device. A perforated open-ended tube of relatively large diameter is inserted into the cap and extends downward into the powder. A flange in the neck of the container acts as a sealing ring.
U.S. Pat. No. 2,981,444 discloses another squeeze-to-use type apparatus. This canister-type dispenser has a feed tube of slightly longer length than the interior of the container. The feed tube has a plurality of holes and when pressure is applied to the container the powder is forced through the holes upward into the mixing chamber and then through the discharge orifice.
U.S. Pat. No. 4,015,753 shows another squeeze-type powder dispensing apparatus. This device employs a vertical dip tube open at the top and bottom ends. While the bottom end of the dip tube is disposed in powder the top end is in communication with the bottom of a hollow spherical mixing chamber in the top of the container. A shorter air tube adjacent to the dip tube is also in communication with the mixing chamber. The powder flows up the dip tube and mixes with air in the mixing chamber before being expelled from the discharge port.
U.S. Pat. No. 4,091,966 discloses another squeeze-type powder dispenser. This patent shows parallel tubes extending down into a cup-like connection fitting at the bottom the dispenser, the bottom of this cup-like fitting having an orifice opening into powder if upright and air if inverted. The parallel tubes are of different lengths with the top of one of the tubes opening into the top of the container and the top of the other tube in communication with the discharge cap.
U.S. Pat. No. 4,261,488 discloses another squeeze container which utilizes a dip tube with a spherical mixing chamber located above it. A cup located at the bottom of the dip tube and in communication with its opening supplies the powdered product up the tube to the mixing chamber and then dispenses powder from the discharge conduit when the container is squeezed.
U.S. Pat. No. 4,307,823 shows a squeeze container with a dip tube connected at its upper end to the orifice of the dispensing head and extending downward at a position spaced from the bottom of the container. A second shorter air tube is positioned around the first tube with its upper end in communication with the top of the container and the air space in the top of the container and its lower end just short of the bottom of the first tube. When pressure is applied, air is forced from the top of the container down in-between the tubes and mixes with the powder at the base of the dip tube and forces the powder up to the dispensing head.
U.S. Pat. No. 4,356,941 shows a squeeze-type dispensing apparatus that utilizes a single continuous dip tube with a plurality of holes which is looped to provide a U-shaped bend positioned in the bottom of the container with one end of the tube in communication with a dispensing nozzle and a closed end of the tube in communication with the interior upper end of the container.
U.S. Pat. No. 4,526,305 discloses a powder distributing apparatus which uses a hollow slotted plug to mix incoming air and powdered material from a collapsible container when squeezed. A cap located on the top of container allows the operator to select the quantity and particle size of the powder dispensed.
Dust dispensing apparatus in the form of designed instruments as well as container applicators employing materials and reliant on restrictive elements are currently in use in increasing numbers. To produce an even flow of the air/dust mixture while maintaining a relatively constant ratio of air to dust and maximizing dissociation of the dust particles is the objective of these devices.
The shortcomings of some of these devices is that their small passages tend to collect and pack dust causing blockage to occur. Others fail to provide adequate movement of air/dust to provide adequate and repeatable flow of material from their exit tubes. Still others will operate only in an upright position while others need to be pointed downward.
The present invention provides a system by which a simple squeeze-type powder dispenser, employable where light dusting is desirable, requiring very low effort relative to the volume of mixture discharged, achieves particle dissociation and dissemination beyond prior art and beyond currently available dispensers.
This invention consists of a tube within a tube pick-up system. An outlet tube resides within a longer, larger diameter dip tube, both secured to the base of a bored-through plug by countersunk holes in the plug""s base. Openings in the dip tube""s opposite ends correspond indirectly to openings in the bottom of the outlet tube midway of the dip tube. When a highly flexible container comprised of an annular wall, a base, a neck and accepts the plug with tubes in place is squeezed, air and dust flow rapidly into the dip tube from both ends and converge at the outlet tube entrance on through the exit nozzle without regard to the container""s orientation.
The object of this invention is to achieve the greatest possible consistency of dispersion of solid particle dusts in the air/dust mixture with the greatest possible directability, range and efficiency of operation in a one-hand, 360xc2x0 operational dusting device.
Another object of this invention is to provide these facilities in a device which may be inexpensively produced from available materials and requiring production of just one simple part.